<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      div p:nth-child(1) ::first-letter {
        color: red;
      }
      /* 错误 */
      /* 答案：p:first-child::first-letter {color: red} */
    </style>
  </head>
  <body>
    <div>
      <p>你好啊</p>
    </div>
  </body>
</html>
